School lunches have become a bit of a hot-button issue. As first lady, Michelle Obama tackled healthier lunches to battle childhood obesity. People got angry. And, when the Trump administration rolled back her initiatives, Obama got angry back.

So, do healthy lunches matter? For a long time, people thought they might be the best way to battle childhood obesity rates. But researchers Justin Gallagher, Michael Anderson, and Elizabeth Ramirez Ritchie say that assumption might not be true.

The good news? Healthy lunches definitely do have an impact. Just not on students’ waistlines. Justin Gallagher, an economics professor at Case Western Reserve University, explains.

Three Takeaways:

Researchers initially wanted to know about the effect of healthy lunches on obesity rates. But they didn’t find a correlation: “We were a bit puzzled at first,” says Gallagher.

One thing they did find? Students who received healthier lunches improved their test scores -- on average -- by four percentile points.

There are better ways to improve test scores, but none as cost-effective as a healthy lunch. For example, reducing the student-to-teacher ratio has been shown to dramatically improve test scores, but at a cost of close to $1,400 for each student. Gallagher estimated that switching to healthier lunches cost about $220 a year.